(1) Field of the Invention
This invention generally relates to a global positioning system (GPS) and radio frequency (RF) communications for underwater vehicles. More particularly, the invention relates to a low cost, highly reliable system for enabling a small scale underwater vehicle to obtain high precision vehicle tracking data.
(2) Description of the Prior Art
In small scale underwater vehicles such as unmanned underwater vehicles (UUV's) and torpedoes, the vehicle deploys a periscope-like device to raise an antenna. The small scale underwater vehicle must operate near the surface and at a very slow speed in order to successfully receive and transmit data. The use of a periscope-type device is both expensive and potentially unreliable.
The following patents, for example, disclose data tracking systems tethered to a submarine or, but do not disclose data tracking systems and an ability to utilize radio frequency communications by deploying an underwater vehicle tether-free of the submarine.
U.S. Pat. No. 3,972,046 to Lombardi; PA1 U.S. Pat. No. 4,227,479 to Gertler et al.; PA1 U.S. Pat. No. 4,533,945 to Lauvray et al.; and PA1 U.S. Pat. No. 5,379,034 to O'Connell.
Specifically, the patent to Lombardi discloses a primary buoy and a secondary buoy that deploys an RF antenna. The primary buoy remains tethered to the submarine and the secondary buoy remains tethered to the primary buoy. The secondary buoy primarily relies on its hydrodynamic shape to develop lift when towed. The Lombardi buoy does not have a launch configuration which allows untethered deployment of an unmanned underwater vehicle from the submarine, or a unique connection between the unmanned underwater vehicle and the buoy. Further, Lombardi does not contemplate the use of a single buoy.
The patent to Gertler et al. discloses a towed communications buoy having a hydrodynamically shaped body. The communications buoy, however, remains tethered to the submarine and is therefore restricted by the speed and depth of the submarine.
Lauvray et al. disclose a communications apparatus towed by a submarine that will rise to the surface at high speeds because of its high buoyancy and low hydrodynamic drag. The Lauvray device, however, also remains tethered to the submarine and is limited by that connection.
O'Connell discloses a device and method of communicating from an underwater vehicle by surfacing an antenna in a towed buoy without surfacing the underwater vehicle. The buoy relies soley on buoyancy to obtain lift and does not appear to rely on hydrodynamic forces. Further, the towing vehicle must slow to allow communication, thus limiting its use.
It should be understood that the present invention would in fact enhance the functionality of the above patents by utilizing an untethered unmanned underwater vehicle having a uniquely deployable single buoy connected thereto which uses hydrodynamic forces to raise the buoy for communication purposes.